A supported iron catalyst is prepared by precipitation of an iron hexacyanoferrate complex onto gamma-alumina. Removal of the cyanide ligands by oxidation at 563 K results in the formation of highly dispersed iron(III) oxide particles. The reduction of the oxidic precursor proceeds via a support stabilised Fe1-xO phase as revealed by in situ magnetization measurements and Mossbauer spectroscopy. Upon exposure of the reduced and subsequently evacuated catalyst to carbon monoxide at room temperature, both linearly and bridged-bonded carbon monoxide species are observed by infrared spectroscopy at wavenumbers of 1985 cm(-1) and 1980-1700 cm(-1), respectively. A fraction of the carbon monoxide reacts with irreversibly chemisorbed hydrogen to formate and small hydrocarbons, which remain bonded on the surface of the iron particles.